UX: Update Setup, Settings, and Help pages with user-friendly text

- Setup: Changed 'Add Keywords' to 'Find Keywords'
- Account Settings: Updated description to be more user-friendly
- AI Settings: Updated description to explain AI models and preferences
- General Settings: Changed to 'App Preferences' with clearer description
- Help: Changed 'Help & Documentation' to 'Help Center' with friendlier description

frontend/src/pages/Settings/Account.tsx

@@ -30,7 +30,7 @@ export default function AccountSettings() {
       <PageMeta title="Account Settings" />
       <div className="mb-6">
         <h1 className="text-2xl font-bold text-gray-900 dark:text-white">Account Settings</h1>
-        <p className="text-gray-600 dark:text-gray-400 mt-1">Account-level configuration</p>
+        <p className="text-gray-600 dark:text-gray-400 mt-1">Manage your account preferences and profile</p>
       </div>
 
       {loading ? (